This invention relates to the field of cancer screening and monitoring.
A major problem in the treatment of cancer remains its early detection. Early detection enables therapeutic treatment from the onset of the disease resulting in successful treatment in many cases.
Numerous studies have demonstrated that tumour cells can express substances liable to be detected in blood and, as a result, liable to be used as tumour markers. It is possible to distinguish between two main types of such substances:
Substances related to tumour presence but which are not involved in tumour formation. Said substances include various proteins (mucins, CA 15-3 and CA 125 markers), protein fragments (cytokeratin fragments, CYFRA 21 marker), enzymes (neurospecific enolase, NSE marker), or oncofoetal antigens such as carcinoembryonic antigens and ACE markers. Such substances, present in normal cells, are altered by the tumoral activity and/or have access to the extracellular compartment due to tumoral necrosis. The detection of such substances is already widely used in clinical practice. However, they only appear when the tumour is established and, as a result, cannot be detected at an early stage.
Substances directly related to tumour formation. Such substances particularly include P53 protein which is produced by a tumour-suppressing gene, and is altered and/or overexpressed in tumours. This alteration and/or overexpression results in a modification of DNA repair control and a higher susceptibility of cells to cell transformation (see T. Soussi et al., 1994; Int. J. Cancer: 57, 1-9). Therefore, P53 protein alterations are the source of tumour formation, in which they represent an early stage. In addition, the presence of autoantibodies directed against P53 protein has been detected in the serum of patients suffering from cancer and the detection of said autoantibodies is under clinical study (C. P. Wild et al., 1995, Int. J. Cancer (Pred. Oncol.): 64, 176-181).
Therefore, substances directly related to tumour formation, such as P53 protein or autoantibodies directed against such protein represent effective cancer markers. However, in view of the increasingly rapid set-up of treatments, it is still necessary to identify new earlier markers. In addition, the markers already described, such as P53 protein, are characteristics of certain types of tumours and are, therefore, not sufficiently polyvalent to diagnose all types of cancer.
The invention relates to a diagnostic process for detecting cancer in a patient including identifying the presence of anti-Csk autoantibodies in a biological sample obtained from the patient. The invention also relates to a diagnostic kit for cancer diagnosis in a biological sample of a subject including Csk protein or a modified form, fragment(s) or conjugates of the substances, reagents to create a medium favorable to an immunological reaction between the Csk proteins or a modified form, fragment(s) or conjugates of the substances and the anti-Csk autoantibodies possibly present in the biological specimen, and one or more reagents which react with Csk proteins or a modified form, fragment(s) or conjugates of said substances and/or anti-Csk autoantibodies and/or immunological complexes, to detect immunological complexes possibly formed.